diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index 472bd3ef69..8c488506fa 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -2565,7 +2565,7 @@ The commands accepted in replication mode are:
         <para>
          Various temporary files and directories created during the operation
          of the PostgreSQL server, such as any file or directory beginning
-         with <filename>pgsql_tmp</filename>.
+         with <filename>pgsql_tmp</filename> and temporary relations.
         </para>
        </listitem>
        <listitem>
diff --git a/src/backend/replication/basebackup.c b/src/backend/replication/basebackup.c
index e4c45c5025..654d0832da 100644
--- a/src/backend/replication/basebackup.c
+++ b/src/backend/replication/basebackup.c
@@ -1072,6 +1072,16 @@ sendDir(const char *path, int basepathlen, bool sizeonly, List *tablespaces,
 			}
 		}
 
+		/* Exclude temporary relations */
+		if (isDbDir && looks_like_temp_rel_name(de->d_name))
+		{
+			elog(DEBUG2,
+				 "temporary relation file \"%s\" excluded from backup",
+				 de->d_name);
+
+			continue;
+		}
+
 		snprintf(pathbuf, sizeof(pathbuf), "%s/%s", path, de->d_name);
 
 		/* Skip pg_control here to back up it last */
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 2a18e94ff4..d30a725f90 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -325,7 +325,6 @@ static void RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok,
 					   bool unlink_all);
 static void RemovePgTempRelationFiles(const char *tsdirname);
 static void RemovePgTempRelationFilesInDbspace(const char *dbspacedirname);
-static bool looks_like_temp_rel_name(const char *name);
 
 static void walkdir(const char *path,
 		void (*action) (const char *fname, bool isdir, int elevel),
@@ -3192,7 +3191,7 @@ RemovePgTempRelationFilesInDbspace(const char *dbspacedirname)
 }
 
 /* t<digits>_<digits>, or t<digits>_<digits>_<forkname> */
-static bool
+bool
 looks_like_temp_rel_name(const char *name)
 {
 	int			pos;
diff --git a/src/bin/pg_basebackup/t/010_pg_basebackup.pl b/src/bin/pg_basebackup/t/010_pg_basebackup.pl
index 455c7fca0d..e6018de054 100644
--- a/src/bin/pg_basebackup/t/010_pg_basebackup.pl
+++ b/src/bin/pg_basebackup/t/010_pg_basebackup.pl
@@ -2,9 +2,10 @@ use strict;
 use warnings;
 use Cwd;
 use Config;
+use File::Basename qw(basename dirname);
 use PostgresNode;
 use TestLib;
-use Test::More tests => 87;
+use Test::More tests => 93;
 
 program_help_ok('pg_basebackup');
 program_version_ok('pg_basebackup');
@@ -76,6 +77,18 @@ my $baseUnloggedPath = $node->safe_psql('postgres',
 ok(-f "$pgdata/${baseUnloggedPath}_init", 'unlogged init fork in base');
 ok(-f "$pgdata/$baseUnloggedPath", 'unlogged main fork in base');
 
+# Create files that look like temporary relations to ensure they are ignored.
+my $postgresOid = $node->safe_psql('postgres',
+	q{select oid from pg_database where datname = 'postgres'});
+
+my @tempRelationFiles = qw(t999_999 t9999_999.1 t999_9999_vm t99999_99999_vm.1);
+
+foreach my $filename (@tempRelationFiles)
+{
+	append_to_file("$pgdata/base/$postgresOid/$filename", 'TEMP_RELATION');
+}
+
+# Run base backup.
 $node->command_ok([ 'pg_basebackup', '-D', "$tempdir/backup", '-X', 'none' ],
 	'pg_basebackup runs');
 ok(-f "$tempdir/backup/PG_VERSION", 'backup was created');
@@ -112,6 +125,13 @@ ok(-f "$tempdir/backup/${baseUnloggedPath}_init",
 ok(!-f "$tempdir/backup/$baseUnloggedPath",
 	'unlogged main fork not in backup');
 
+# Temp relations should not be copied.
+foreach my $filename (@tempRelationFiles)
+{
+	ok(!-f "$tempdir/backup/base/$postgresOid/$filename",
+	   "base/$postgresOid/$filename not copied");
+}
+
 # Make sure existing backup_label was ignored.
 isnt(slurp_file("$tempdir/backup/backup_label"),
 	'DONOTCOPY', 'existing backup_label not copied');
@@ -206,6 +226,19 @@ SKIP:
 	ok(-f "$pgdata/$tblspc1UnloggedPath",
 		'unlogged main fork in tablespace');
 
+	# Create files that look like temporary relations to ensure they are ignored
+	# in a tablespace.
+	my @tempRelationFiles = qw(t888_888 t888888_888888_vm.1);
+	my $tblSpc1Id = basename(dirname(dirname($node->safe_psql('postgres',
+		q{select pg_relation_filepath('test1')}))));
+
+	foreach my $filename (@tempRelationFiles)
+	{
+		append_to_file(
+			"$shorter_tempdir/tblspc1/$tblSpc1Id/$postgresOid/$filename",
+			'TEMP_RELATION');
+	}
+
 	$node->command_fails(
 		[ 'pg_basebackup', '-D', "$tempdir/backup1", '-Fp' ],
 		'plain format with tablespaces fails without tablespace mapping');
@@ -232,6 +265,20 @@ SKIP:
 	ok(!-f "$tempdir/tbackup/tblspc1/$tblspc1UnloggedBackupPath",
 		'unlogged main fork not in tablespace backup');
 
+	# Temp relations should not be copied.
+	foreach my $filename (@tempRelationFiles)
+	{
+		ok(!-f "$tempdir/tbackup/tblspc1/$tblSpc1Id/$postgresOid/$filename",
+		   "[tblspc1]/$postgresOid/$filename not copied");
+
+		# Also remove temp relation files or tablespace drop will fail.
+		my $filepath =
+			"$shorter_tempdir/tblspc1/$tblSpc1Id/$postgresOid/$filename";
+
+		unlink($filepath)
+			or BAIL_OUT("unable to unlink $filepath");
+	}
+
 	ok( -d "$tempdir/backup1/pg_replslot",
 		'pg_replslot symlink copied as directory');
 
diff --git a/src/include/storage/fd.h b/src/include/storage/fd.h
index 4244e7b1fd..e49b42ce86 100644
--- a/src/include/storage/fd.h
+++ b/src/include/storage/fd.h
@@ -124,6 +124,7 @@ extern void AtEOXact_Files(void);
 extern void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
 				  SubTransactionId parentSubid);
 extern void RemovePgTempFiles(void);
+extern bool looks_like_temp_rel_name(const char *name);
 
 extern int	pg_fsync(int fd);
 extern int	pg_fsync_no_writethrough(int fd);